D-STAR - What is it?
W4BUG has made a big step for us. We decided to do our part to advance amateur radio by installing and operating an ICOM D-Star repeater for use by the amateur community in our area. An ICOM repeater will be installed at the Imperial Point Hospital that consists of the controller, a 1.2G repeater, a 440 repeater, and a 144 repeater. It will use the internet to connect to other repeaters, as well as, RF.
Surely, most operators are pretty miuch in the dark as to what D-Star is and what it means to them. This page is an attempt to help explalin the system and start you on your way to understanding the system.
D-STAR (Digital Smart Technologies for Amateur Radio) is a digital voice and data protocol specification developed for use in amateur radio. D-Star compatible radios are available on VHF and UHF amateur radio bands. In addition to the over-the-air protocol, D-Star also provides specifications for network connectivity, enabling D-Star radios to be connected to the Internet or other networks. D-STAR is the result of research by the Japan Amateur Radio League to investigate digital technologies for amateur radio. To date, other than ICOM - no other amateur radio equipment manufacturer has chosen to include D-Star technology.
D-STAR transfers both voice and data via digital encoding over the 2 m (VHF), 70 cm (UHF), and 23 cm (1.2 GHz) amateur radio bands. Voice is encoded as a 3600 bit/s data stream using proprietary AMBE encoding, with 1200 bit/s FEC, leaving 1200 bit/s for data encoding. On air bit rates are 4800 bit/s over the 2 m, 70 cm and 23 cm bands. Digital only data can be sent at 128 kbit/s only on the 23 cm band. Radios providing data service use a RS-232 or USB connection for low speed data (1200 bit/s) and Ethernet for high speed (128 kbit/s) connections to allow easy interfacing with computer equipment.
As long as the signal strength is above a minimum threshold, the quality of the data received is better than an analog signal at the same strength. It is capable to linking repeaters together and through the Internet, so HAMS may talk to another HAM radio in a different state.
Another important aspect of D-STAR technology is its ability to send large quantities of data to emergency responders in the event of a disaster. Served agencies can instantly relate to sending "email" or a "word files" to someone. The data sent can be high-volume, where traditional amateur radio "modes" are capable of getting a message through albeit slowly, D-STAR can place documents into the hands of those that need them most - fast image, text and document data exchanges.
The gateway control software rs-rp2c, runs on Fedora Core 2+ or Red Hat Linux 9+ OS on a Pentium grade 2.4 GHz or faster machine. The machine running the gateway control software contains two NICs. A Router such as the WRV54G from LINKSYS connects into the two NICs.
Our DStar is currently under construction by it's new owner, Dirk Basting, N4AN. He hopes to have it up and running soon.